Wheat is the second most important cereal
in Kenya. However, production is severely constrained by both abiotic and
biotic stresses.
We have ever said that a research found wheat
has allelopathic potential,it is so eco-friendly.But to itselt,it can’t
protect itself very well.
Severe infestations by russian wheat aphid (RWA)
may result in yield losses of up to 90% while stem rust (Race “Ug99”) infected
fields may suffer 100% crop loss. The two pests combined are seriously
affecting wheat farmers’ incomes because of the heavy reliance on pesticides
that increase the cost of production.
An article from American Journal of Plant Sciences
studies three wheat varieties,and try to find a good wheat lines that is resistance
to russian wheat aphid and stem rust:
“Kwale”, a Kenyan high yielding variety but susceptible to both RWA
and “Ug99”; “Cook”, an Australian variety carrying stem rust resistance gene
Sr36 conferring immunity to “Ug99”; and “KRWA9”, a Kenyan line with resistance
to RWA but of poor agronomic attributes were used. A double cross F1 (DC F1)
was obtained by crossing the F1 of “Kwale × Cook” and the F1 of “Kwale ×
KRWA9”. The DC F1 population was subjected to sequential screening for both RWA
and “Ug99” resistance. Surviving DC F1 progenies were left to self pollinate to
obtain the F2 of the double cross (DC F2). The DC F2 progenies were
sequentially screened against RWA and “Ug99” to yield a population that was
resistant to both RWA and “Ug99”. Genotyping of the DC F2:3 families were
conducted to select homozygous resistant plants. Data indicated that the RWA
and “Ug99” resistance genes were successfully pyramided. Though races with
virulence for Sr36 have been reported, the gene provides immunity to race
“Ug99” and can still be effectively used as a component for “Ug99” resistance
breeding together with other Sr genes.
(source:SCIRP/ American Journal of Plant Sciences)
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